I have a couple of questions that i would like to ask the experts if possible.I can't get the green eye to open up when testing different capacitors.The green eye is lite but like i say will not open up.Also,can you get into the back of the IT 28 to check the unit for tubes-resistance and also to check for bad capacitors in unit.I can't seem to get the back off and I don't want to mess up the back cover to the unit.I bought a book for this unit so i do have some direction with this book.Thanks<P>------------------<BR>

You can do a few things even without the manual. If you have the capability, check the 1629 on a tube tester. Many tube testers did have provisions for testing 'eye' tubes. <BR>Then, the socket often has a pair of 1Meg resistors; test those. After that, wait for the manual; they usually had a troubleshooting chart. <P>------------------<BR>"You can lead a horticulture, but you can't make her think."

Hi jrj,<BR>There must be a way to get the back cover off easily. Im not familar with this model,but I would think there would be a couple of screws in the back somewhere.Or maybe you have to take the knobs off and the chassis slides out the front. The Heathkit constuction manual should be able to tell you how it comes apart.<BR>Don<P>------------------<BR>

The back cover is spot welded to the side cover as one piece. There should be two screws on the back that holds it on. You don't need to remove anything from the front panel to seperate the back cover.<P>------------------<BR>

Paul is correct. The back and the sides/top/bottom come off all in one piece. Or, you could say the front comes forward, leaving the rest. You don't have to remove any knobs or lever tips. <BR>Once you get the manual, it does have a calibrating section, and some troubleshooting tips. I spoke out of turn when I mention a chart; Heathkit and Eico sometimes do have this. It may be something simple, or at worst it is a bad tube. <BR>I looked over my manual, and the eye tube is a 6E5. Because a lot of old radios use a 6E5, people like AES want an arm and a leg for them. So be careful. The 1Meg resistor is between pin #2 and pin #4. There is only a pair of capacitors left to the wiring to that eye tube, so there cannot be much to go wrong. If you calibrate, and the eye isn't opening or closing, the tube is probably bad. According to the schematic, there ought to be 200VDC on pin #4, 22VDC on pin #2, and -0.8VDC on pin #3. Pin #5 is grounded. That's all there is to the eye circuit. <P>------------------<BR>"You can lead a horticulture, but you can't make her think."

Vintage test gear,unless you buy one from a guy who recently rebuilt it is **always** in need of a complete restoration before you even dare think of using it to test anything,at all,period,ever,under any circumstances whatsoever,end of story.<P>Replace all caps(except maybe mica and ceramic) check and replace resistors as needed and then calibrate.<BR>And,never never ever buy anything electrical until you first determine that the schematic at least(and whole manual,preferably) is available at a price you are willing to pay.<BR>Malcolm<P>------------------<BR>A closed mind is the worst of all prisons.

This unit has a green eye RCA D1 in place of a 6e5 6g5 6t5 and 6u5 which is suppose to work in a heathkit IT28 CAP CHECKER.i not found D1 tube in my tube guide but i Checked accordinly to other tubes and it checked bad>(6 pin)just like the other ones that are suppose to work in Heathkit.Any suggestions.Thanks JRJ<P>------------------<BR>

Have you replaced the filter capacitors and paper capacitors, checked the tubes with a tube tester, checked the resistors for proper value, done the voltage checks. <P>If these steps have not been done there is not much we can help you with, you can't do any trouble shooting until you have replaced the defective components.<P>Dave<P>------------------<BR>Intelligence is the ability to use your knowledge